Changed LED output pin from PB5 to PB7

Somehow made a mistake - LED is connected to PB7, not PB5.
Added some flashy LED code for debugging.
Played around with UART config settings.

Played around with UART config settings to see if I could
get the Mega32C1 to respond - I couldn't :o(
Added output of a byte 0xAA during USART initialisation.

MEGA32C1 seems to need a kick-start to get it up and running.
Added the output of a byte of data via LINDAT. Now AVRDUDE seems to
be able to communicate a bit.